<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <div id="main" style="width: 600px; height: 400px"></div>
    <button onclick="highlightData()">高亮数据</button>
    <button onclick="toggleLegend()">切换图例</button>
    <button onclick="showTooltip()">显示提示框</button>
    <button onclick="selectData()">选择数据</button>

    <script>
let obj1 = { name: 'tom' }
let obj2 = { name: 'jack' }

const weakSet = new WeakSet([obj1, obj2])

obj1 = null
obj2 = null
    </script>
  </body>
</html>
